BBVA has been relying on Mexico, which is its biggest market and accounts for 41 percent of its overall profits, to offset worsening economic conditions in Turkey and an ongoing squeeze on lending activity in Spain.

“Incoming president (Andres Manuel Lopez) Obrador had previously indicated a more business-friendly approach than the market initially feared, but this proposal will likely increase jitters once more that his policies may prove more interventionist in nature,” Jefferies said in a note.

Shares in BBVA fell as much as 6.3 percent and were down 5.0 percent at 4.909 euros at 1057 GMT to lead the declines on Madrid blue-chip IBEX35.

In Mexico, the bank’s net profit climbed 18.5 percent to 642 million euros ($730.34 million) in the third quarter, underpinned by stronger lending activity.

Like Spanish rival Santander, BBVA makes most of its profit overseas, a model that helped it to counter a double-dip recession at home in recent years.

Shares in Santander, which makes 7 percent of its net profit in Mexico, fell around 2 percent.